1. Field of the Invention
The present invention relates to a sensor device having a housing base part, a bearer part, a chip structure situated on the bearer part, and a spring/damper device via which the housing base part and the bearer part are elastically connected to one another.
2. Description of Related Art
Sensor devices used for example in safety systems of motor vehicles standardly have a chip structure that has one or more sensor chips as well as an evaluation chip. The sensor chip is fashioned in the form of a micromechanical component (MEMS: Micro Electro Mechanical System) having movable functional elements in order to acquire a physical measured quantity, such as an acceleration or a rate of rotation. The evaluation chip is used to control the sensor chip, and for the evaluation or further processing of measurement signals of the sensor chip.
A requirement of such sensor devices is that the sensor chips should be decoupled from external mechanical influences, such as vibrations, in order to enable a precise measurement. In a sensor chip for acquiring a rate of rotation, for example, functional elements are excited to oscillate at a prespecified operating frequency. A change in the operating frequency due to external influences causes impairment or falsification of the measurement. Therefore, the chip structure is mounted in a housing that enables a sufficient damping—in the case of a rotational rate sensor, at its operating frequency in particular.
Published German patent document DE 10 2006 026 878 A1 discloses a sensor device having a bearer part for accommodating a chip structure that is situated horizontally inside a frame-shaped housing base part. In an intermediate space between the bearer part and the housing base part, an elastic material is fashioned so that the bearer part can be elastically deflected relative to the housing base part, and a spring suspension or damping of the chip structure is enabled. However, the horizontal situation of the bearer part inside the housing base part entails a relatively large space requirement.
For the electrical contacting, the frame-shaped housing base part has contact elements that are connected to the chip structure situated on the bearer plate via free-standing bonding wires. However, this design results in a low fall stability of the sensor device. A deflection of the bearer part relative to the housing base part that occurs when there is an impact can cause a compression or plastic deformation of the bonding wires, resulting in contacts between the bonding wires and thus to undesired short-circuits in the operation of the sensor device. It is also possible for the bonding wires to be torn or detached from their contact points, interrupting the electrical connection.